Vulcanized copolymers of drying oils and diene hydrocarbons



hardens only slowly and the interior of a thick The pr parat on of a suitable resin for use in Patented July 12,1949 2,475,664;

UNITED STATES PATENT OFFICE- VULCANIZED COPOLYMERS F DRYING OILS AND DIENE HYDROCARBONS Howard L. Gerhart, Milwaukee, Wis., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa.,. a. corporation of Pennsylvania No Drawing. Application May 23, 1945,

Serial No. 595,479

22 Claims. (01. 260423.?)

The present invention relates to the hardening In the practice of the invention, a copolymer of unsaturated resins of the addendum type and resin is prepared by admixing and copolymerizing it has particular relation to the hardening of the unsaturated glyceride oils, cyclopentadiene or its resins obtained by conjointly polymerizing a mixlower polymers, above mentioned, and'which may ture of cyclopentadlene or a lower polymer 5 therefore be termed a diene compound consisting (dimer, trimer, tetramer, or pentamer) and an of one or more five sided rings, empirically of the unsaturated glyceride oil. formula (CsHo) there being present in each mole- Some of the objects of the invention are cule at least two double bonds. Methods of poly- A. To provide a simple and convenient method merizing mixtures of these materials to form of quickly converting relatively tacky, easily deresins are-disclosed in my. copending applicaformable, and slow hardening addendum resins tions: Serial No. 512,769, filed December 3, 1943,

intoahard and durable state; Patent No. 2,387,895; Serial No. 323,944, filed B. To provide as a new product a hard, infusi- March 14, 1940, Patent No. 2,392,732; Serial No. ble, resinous product comprising a copolymer of 512,766, filed December 3, 1943, Patent No. cyclopentadiene or its lower polymers and an 2,392,142. unsaturated glyceride oil; These all disclose conjointly polymerizing a C. To prcvlde a plastic composition which glyceride oil such as linseed oil, and monomeric readily wets fibrous materials or fillers such as or polymeric cyclopentadiene. Polymerization asbestos, and which still can be readily hardened may be effected by heating a mixture of oil and by application of heat; 29 cyclopentadiene say to a temperature of 50 or D. To provide a composition which is partieu- 60 C. in the presence of a catalyst such as tin larly adapted for use as a friction element in tetrachloride or preferably by heating Oil and a brake linings, clutches, and thelike. lower polymer of cyc pen lene. ea dimer It has heretofore been proposed to provide an in a closed s t m o a airl hi h temperature addendum resin by coniointly polymerizing cer- (200 or 800 C.) until th Pr d c i f d sired taln cyclicdiene hydrocarbons, notably e el consistency. Considerable variation of the ratio pentadiene o its lower polymers and an t of oil to cyclic hydrocarbon is admissible, though rated glyceride oil such as linseed oil, soya bean products Containing a fa r y hi h ratio of hydrooil, tung oil, or the like. These copolymer resins carbon are desirable. In most instances, the ratio have been admixed with fibrous material such as 30 f lo ntadi e or i lower polymer will be asbestos fibers and after baking have been emabove based p n the y bon ployed as the friction elements in brake drums mixture and not much above 70% upon the same and friction clutches. This -material, however, bflSiS- body such as'a brake band or a clutch plate will the practice of the invention is illustrated as retain a certain degree of tack and flow for a very w A mixture of about 4 Par s y Wei ht long period of time, 7 of bodied linseed oil and 35 parts by weight of The present invention contemplates a method 'dlcyclopentadiene was heated according to th of treating the foregoing materials whereby they following schedule in an l are easily, economically, and quickly hardened to 40 an infusible resistant state in which they are Time r. Pressure viscosity eminently suited for use as friction elements in brakes, clutches, and the like. As one feature, 0m

the invention consists in the incorporation of 295 the copolymer resin with sulphur and its subse- $3311 252 5 3 quent subjection to a baking operation in order 35 to effect vulcanization. Another feature or the 3%: 38 invention includes the incorporation of certain esters such as pentaerythritol esters of acids from 0 25:81: 2% 1 linseed oil or other animal or vegetable oil, notably Drop of an unsaturated nature to promote wetting of l fillers such as asbestos fibers, etc. A still further wh the mixture in the autoclave has reached feature involves the incorporation of so-called a viscosity of "E" at 50% in petroleum naphtha, friction dusts such as diatomaceous earth or the it is dropped from the autoclave into a quantity like to improve the friction characteristics. 55 or naphtha sufilcient to give a solution of.

amass:

the resin in the naphtha; that is, the total solid resin content is 70%. This constitutes the vehicle for the molding operation.

If a tougher product is desired,'the ratio of dicyclopentadiene'to oil may be increased: One

such formulation would comprise: linseed oil- 40 parts by weight, dicyclopentadiene-Eill parts by weight. Such mixture copolymerizes somewhat faster than the one given above. Reaction conditions are otherwise substantially identical.

The resins after preparation may be admixed with or dissolved in a suitable solvent medium such as petroleum hydrocarbon, naphtha, or the like. A small amount of sulphur and a filler such as ground asbestos, wood flour, macerated cloth, walnut shell fiour, cotton fibers, cloth fillers, fiber glass or other inert filler materials are added. Preferably the amount of'the solvent medium is suflicient to provide a putty-like mass which is sufficiently plastic to be extrudable or moldable into desired configuration. Vulcanizing agents including'sulphur; and vulcanization accelerators such as mercaptobenzothiazole, benzothiazeyldisulphide, diphenylguanidine, hexamethyltetramine, thiuramdisulphide, piperidinium pentamethylene dithioearbamate, mixtures of methylene dianilide and formaldehyde aniline, condensation product of acetaldehyde and aniline, zinc dibutyl dithiocarbamate, zinc diethyl dithiocarbamate, and the like may also be introduced.

Other modifying agents such as zinc oxide,

stearic acid, carbon black and the like can also include the appropriate amounts; A convenient ratio of zinc oxide and stearic acid would, for example, be approximately of the range of to per cent respectively.

Example! A convenient formulation in parts by weight would be approximately as follows:

Parts oil-cyclopenta'diene copolymer 80 Sulphur a 3 vulcanization accelerator 1 Ground asbestos 300 Enough gasoline or naphtha is added to render the mixture extrudable.

In the manufactureof brake bands, the mixtures are extruded preferably as continuous strips which are cut to appropriate length, placed in,

molds of desired configuration, and then subjected to cure first preliminary at 75 C., and finally at a baking temperature of about 150- 7200" C. for a period of one to five hours. 7

7 Example II In a second formulation, a mixture of:

. Parts Fibrous asbestos (containing diatomaceous earth) 3975 Sulfur Accelerator 8 'AbOVe resin (70% solids) .1150 Gasoline -r- 255 hardness to mold these mixtures under from 100-1000 lbs./sq. in. pressure before the curing process. The entire curing process may take place inthe mold or as a convenience, it is possible to simply use the molding operation to preform the piece and to complete'the cure in an oven. 7

It has been found that the addition of 600 parts of water to the mixture in the Banbury mill will enable the extrusion process to proceed more easily because water improves the flow of the mixture through the die. Where asbestos fibers are present the Wetting characteristics of the compound with respect to th fibers may be improved by the addition'of a small amount of water to the mixture. Approximately 21% of water, based upon the weight of the compound is sufficient though more or less may be employed.

In order to improve the mixing characteristics of the compound with respect to the asbestos fibers, it maybe desirable toincorporate an appropriate amount of a modifier such as pentaerythritol esters of unsaturated acids of fatty oils such as linseed oil. pared by the simple esterification of one mol of pentaerythritol and three mols of linseed oil acid.

As previously stated, the mixture may also include a friction material such as diatomaceous earth designed to improve the coefllcient of friction of the material with respect to brake drums or friction plates. This ingredient is includedin substantially any desired ratio although approximately 20% based upon the weight of the total mixture willbe satisfactory for the purpose.

The embodiments of the invention herein disclosed are merely to be considered as examples. It will be apparent to those skilled in the art that numerous modifications may b made therein without departure from the spirit of the invention or the scope of the appended claims.

What I claim is:

1. As a new product the molded, hard, infusible vulcanizate of sulfur and a copolymer of a glyceride drying oil and a diene hydrocarbon of a class consisting of cyclopentadiene and its lower homopolymers up to the pentamer.

2. The product as defined in claim 1 in which the oil is linseed oil.

3. The product as defined in claim 1 in which the vulcanizate is admixed with asbestos fibers.

4. A new product as defined in claim 1 in which the vulcanizate includes asbestos fibers and pentaerythritol esters of fatty acids.

5. A product as defined in claim 1 which further includes wood flour;

6. As a new product, a hard infusible vulcanizate of sulfur and a copolymer of a glyceride oil and a diene hydrocarbon of a class which consists of cyclopentadiene and its lower homopolymers up to the pentamer and an inert filler.

7. A friction element for brake bands, clutches, and the like consisting of the product defined in claim 1 molded tosuitable form and containing an inert fibrous filler. i

8. A molding compound comprising a copolymer of a drying glyceride oil and a diene hydrocarbon of a class consisting of cyclopentadiene and its lower polymers up to the pentamer, said.

copolymer being mixed with an inert filler ma- Suitable esters may be preterial to form a plastic moldable composition. and sulfur for vulcanizing the copolymer.

9. A composition as deflned'in claim 8 which is of improved extrudability by reason of the presence therein of water.

10. A method of preparing a vulcanized resin product which comprises mixing a copolymer of a drying oil and cyclopentadiene with 3 to 20% of sulfur based upon the weight of resin of sulfur and heating the mixture to a temperature of 150 to 200 C. until it is cured to a hard and infusible state.

11. A method of preparing a vulcanized resin product which comprises mixing a copolymer of cyclopentadiene and a drying oil, with about 3 to 20% of sulfur based upon the copolymer resin and heating the mixture untilit is cured to a hard infusible state. 1

12. A method of preparing a vulcanized resin product which comprises mixing with sulfur a copolymer of a drying oil and a diene hydrocarbon of a class which consists of cyclopentadiene and its lower homopolymers up to the pentamer, the hydrocarbon being in a range of 50 to 70% of the copolymer to provide a mixture containing 3 to 20% of sulfur based upon the resin content and heating the mixture until it is cured to a hard infusible state.

13. A method of preparing a vulcanized resin product which comprises mixing with sulfur a copolymer of a drying oil and a diene hydrocarbon consisting of 1 to 5 CsHs groups in the form of five sided rings per molecule, the hydrocarbon being in a range of 50 to 70% of the copolymer, and heating the mixture until it is cured, curing beingeifected at a temperature of 150 to 200 C. for a period of 1 to 5 hours.

14. A vulcanizate of sulfur and a copolymer of a drying oil and acyclic diene hydrocarbon consisting of 1 to5 CsHs five sided rings per molecule, the hydrocarbon comprising 50 to 70% of the copolymer.

15. A sulfur vuloanizate of a copolymer of a drying oil and a cyclic diene hydrocarbon containing 1 to 5 C5HB five sided rings per molecule, the hydrocarbon comprising 50 to 70% of the copolymer and the sulfur being in a range of 3 to 20% based upon the resin.

16. A composition adapted to be shaped and cured to provide a friction element, said comto 20% of sulfur, inert filler and a hydrocarbon. solvent of the copolymer in an amount to form a putty-like extrudable mass.

17. The friction body obtained by heating a shaped portion of the composition defined in claim 16 to the temperature of vulcanization until it is cured to a hard, durable state.

18. A process of forming a friction body, which process comprises mixing a copolymer of a glyceride drying oil and a diene hydrocarbon containing 1 to 5 CsHe five sided rings per molecule, the hydrocarbon constituting to of the copolymer, with 3 to 20% of sulfur by weight upon the basis of the resin content, inert filler and a petroleum hydrocarbon solvent for the copolymer to form'a putty-like mass, shaping the mass to desired form and vulcanizing it by application of heat and pressure to a hard infusible state.

19. A process as defined in claim 18 in which vulcanization is efiected by -application of a temperature of 150 to 200 C. for a period of 1 to 5 hours. r

20. A composition as defined in claim 16 which further contains a rubber vulcanization. accelerator.

21. A composition as defined in claim 16 in which the copolymer and the inert filler are in about the ratio of and 300 parts by weight.

22. A process as'defined in claim 18 in which the copolymer and filler are added in the ratio of 80 and 300 parts respectively and the mixture is cured at a temperature of to 300 C.

HOWARD L. GERHART.

REFERENCES CITED The following referenlces are of record in the file of this patent:

Soday Feb. 12, 1946 

